The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
All publications identified herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Transfection processes are used to deliver various types of materials into a cell, and there are numerous known methods in the art. For example, U.S. Pat. No. 5,586,982 describes a treatment device capable of delivering genetic material or drugs into cells of a patient in vivo using heat to assist with transfection. Unfortunately, such approach often tends to damage the cells. Moreover, since the poration lasts only for a very short time, the amount of material delivered into the cells will in most cases be significantly reduced, especially where the material is relatively large. Finally, such approach also fails to provide a method for culturing cells after transfection.
In another example, as described in US 2009/0081750, magnetic fields are employed to move cells through a channel in which the cells undergo transfection. Actual transfection is then performed via several possible manners, including electroporation, heat, or light. Similar to the '982 reference, effective transfection is typically limited to relatively small molecules and low quantities. Yet another example of poration to transfect cells is described in WO 2013/059343. Here, cells are fed through a microfluidic channel in a buffer that contains a delivery material. The cells pass through a constriction region, which causes the cells to become perturbed with pores through which the delivery material then diffuses. While this approach overcomes to at least some degree issues associated with short pulse time, delivery still requires poration.
A more extreme approach is presented in U.S. Pat. No. 5,858,663 in which a cold gas shockwave is used to accelerate micro projectiles that carry matter into the cells. While such approach guarantees delivery of even relatively large molecules into a cell, it is readily apparent that such approach is also prone to significantly damage a cell.
WO 96/24360 attempts to overcome shockwave damage by providing a time-dependent impulse transient characterized by rise time and magnitude that is thought to increase the overall permeability of a cell membrane, which results in an increase in diffusion of materials into the cell. The impulse is achieved by applying an optical field to a film on which the cells are grown, and the optical field ablates the film thereby delivering the impulse. While such approach will provide for transfection, high throughput production of transfected cells remains problematic. To increase throughput, WO 02/42447 teaches use of leverages shock or other forms of pressure, and U.S. Pat. No. 7,687,267 describes a high throughput cell transfection device for transfer of small nucleic acid molecules (e.g., DNA, siRNA) through electroporation where the device contains an array of cell transfection units. Similarly, US 2012/0244593 teaches a high throughput electroporation transfection device, which requires poration (i.e., electroporation) and diffusion to deliver the material.
Interestingly, the known transfection devices require significant disruption to a cellular membrane to allow for greater diffusion of cargo material, which becomes especially difficult where the cargo material is relatively large. Therefore, there is a need for improved transfection devices and methods suitable for delivery of cargo of various sizes, and especially large cargo of 1 μm or larger, through a cellular membrane that will not or only minimally adversely affect the cell.